<!DOCTYPE html>
<html>
	<head>
		<meta charset="utf-8">
		<title>闭包精细版</title>
	</head>
	<body>
		<script type="text/javascript">
			var x = 1;
			/* ()里面必须是表达式,声明会消失 */
			if (function f() {}) {
				/* typeof undfind  输出的是string */
				x += typeof f;
			}
			/* 1undefined */
			console.log(x)
		</script>
	</body>
</html>
